Intro: Replace Broken Penknife Handle
I have a Victorinox penknife. Actually, I have many, but the one in question is a "dress" knife, meaning it is the extra-small size. One of the plastic side pieces had shattered when the knife fell onto the roadway. It was uncomfortable to hold and use, so had been filed in a drawer for a few years.
Then this 'Ible was posted by Felix_H. Massive hat-tip for his inspiration.
Having suddenly realised that it was possible to effect a repair, I leapt into action.
To make and fit the new side, I used:-
thin strips of hardwood
PVA glue to laminate the wood
epoxy resin to fit the completed piece
Danish Oil to seal and finish the timber
Tools employed were:-
a tenon saw to cut the hardwood strip
a razor saw for the coarse shaping
a very narrow chisel for carving out the tweezer storage
various grits of sandpaper to shape and finish the wood
small drill and drill-press to drill shallow blind holes
Step 1: Make Plywood
Felix_H used some very nice looking plywood, with the various layers on display.
I did not have any nice ply, and I wasn't too concerned about appearance, so I decided to use some hardwood and make my own plywood.
First of all, I took all the measurements from the knife for what size the replacement part would be, and drew a life-size template in LibreOffice, which I could print out and use as a pattern. The file is attached above.
I had a 2mm (about 1/8") thick strip of ash, cut from a broken bell stay. This was not wide enough to allow pieces to be cut fully across the grain, so I cut two strips at an angle and laid them against one another so that there was as much crossover of the grain as possible.
A very thin smear of PVA woodglue, some vigorous clamping and 24 hours for curing left me with an oversized piece of two layers of wood.
Step 2: Fit Wood to Knife
One of the paper templates was stuck to the cured plywood with double-sided tape and then a shallow blind hole was drilled to match the studs on the knife body. The holes were drilled at 4mm wide to allow for a bit of error in placement, and some room for epoxy in the hole when assembled.
Once the holes were drilled, the knife was offered up to make sure that everything was in the right place and the wood would (geddit) fit.
Then the wood was cut down to the right width using an Xacto razor saw.
A visual and fit check meant that a little more sanding was needed to get the width perfect. Remember to separate your knife from the wood before sanding to avoid scratching the metal.
Step 3: Fit Tweezers
Felix_H hadn't included any side-stowed tools, but I have always found the tweezers in a Victorinox to be amazingly useful. Actually the toothpick is pretty useful too, as it is exactly the right size to set the spark plug gaps on a Volvo B21A engine.
However, as I have no need to set plug gaps on a Volvo, I decided to fit the tweezers.
Please note that the original knife cover held both, but I decided that was in the too-hard basket for the first attempt.
I laid the tweezers against the wood and marked the area which needed to be removed using a pen.
I drilled a short blind hole at the inward end of the slot to discourage the wood from splitting, and then used the razor saw to cut the sides of the groove.
The mass of the material was removed using a 4mm (3/16") chisel.
Finally, the tweezers were checked for fit against the carved channel. That photograph is out of focus for reasons of focus.
Step 4: Cut Access Notch
To allow the tweezers to fit flush against the end of the knife, there needs to be a gap cut into what will be the rounded area.
With the wood held securely, the razor saw was used to make four or five parallel cuts within the width of the channel to the required distance. Then the material was pared out using the chisel.
A small extra piece of wood came away here, which was an unfortunate side-effect of the bias-cut ply I had made.
Step 5: Final Shaping
With the wood fitted to the knife I marked where the curve at the end should be, then used 40grit sandpaper to remove material and put a chamfer around the edge of the wood.
When the wooden piece was the correct shape and size, finer grades of sandpaper were used to remove sanding marks and leave a nice smooth finish.
Step 6: Fix Handle and Finish
Felix_H used superglue to attach his handle, but I've never had much luck with that, so I used a slow-set two-part epoxy. This is mixed, rested for ten minutes, remixed and applied, and then left to cure for a day.
Since the mushroom-head studs on the knife fitted loosely into the holes I had prepared, I put a dab of epoxy onto each stud, and smeared a very thin layer on the flat contact surfaces.
The epoxy does not need tight clamping, so I just left it in a couple of spring clamps to hold it securely while the resin cured.
Once that was set, I used a fine grade of paper to put a final polish on the wood, and then gave it a couple of coats of Danish Oil, sanding finely between coats.
End result: a knife which I can now carry on my keyring without worrying about the metal snagging on anything, and with a handle which not only functions, but also looks nice, feels interesting and is a conversation piece.
Now all I need to do is find a replacement spring for the scissors on that knife.